Internal combustion engines operating with direct injection (DI: direct injection) offer high potential for reducing fuel consumption with relatively low pollutant emissions. In contrast to intake manifold injection, with direct injection fuel is injected under high pressure directly into the combustion chambers of the internal combustion engine.
Injection systems having a central accumulator (common rail) are known for this purpose. In common rail systems of said type, a fuel pressure regulated via a pressure sensor and a pressure regulator by the electronic control device of the internal combustion engine is built up in the common rail by means of a high-pressure pump, which fuel pressure is available largely independently of the engine speed and the quantity of fuel injected. The fuel is injected into the combustion chamber via an electrically controllable injector. This receives its signals from the control device. Through the functional separation of pressure generation and fuel injection, the injection pressure can be selected substantially freely independently of the current working point of the internal combustion engine.
For enhancing the performance and torque of internal combustion engines it is known how to provide a boosting facility that increases the charging quantity through precompression, with a charger conveying fresh air into the cylinder of the internal combustion engine. With mechanical boosting the compressor is driven directly by the internal combustion engine (compressor boosting, for instance), whereas with exhaust gas boosting a turbine (exhaust gas turbine) to which the exhaust gas of the internal combustion engine is applied drives a compressor located in the intake manifold of the internal combustion engine.
To reduce the charge-changing losses, modern internal combustion engines have variable valve drives with single- and multi-stage or continuous variability. The variable valve control of the intake and exhaust valves offers the possibility of setting the valve control times within the physical limits of the existing actuator principle (mechanical system, hydraulic system, electrical system, pneumatic system, or a combination of the cited systems) more or less freely. Savings in consumption, lower raw emissions and a higher torque can be achieved as a result.